Wind turbines are provided with a rotor shaft which is part of an electrical generator producing electricity during movement of the rotor relative to a stator of the generator. The stator comprises a number of coils, the rotor comprises a number of permanent magnets so that an electric voltage is induced when the rotor is turned. Typically the rotor comprises three wind turbine blades.
Conventionally vortex generators are attached on wind turbine blades in order to reduce a tendency of separation of the air flow on the surface of wind turbine rotor blades. Another effect is that vortex generators counteract stall.
In WO 00/15961 A1 a wind turbine blade comprising multiple vortex generators is disclosed. Each vortex generator is wedge-shaped and extending perpendicularly out from the blade surface. There is a high risk of the vortex generators being damaged or torn off during handling of the blade, e.g. when the blade is lifted in lifting straps, due to the fragile design of the vortex generators. Vortex generators may be formed integrally with the blade, whereby each vortex generator is produced as a separate member having a bottom face which is secured to the surface of the blade by adhesion.
In WO 2008/113350 A2 a wind turbine blade with multiple vortex generators is proposed which are arranged in two or more parallel rows.
Another wind turbine blade with vortex generators is known from EP 1 314 885 A1. The vortex generators are arranged on a strip which is fixed on a surface of the rotor blade.
Experience has shown that high centrifugal forces and aerodynamic forces acting on the attached strips of vortex generators pose a risk for them to rip off over time Vortex generators installed at the tip end part of the rotor blade are worst affected by this problem. The efficiency of the vortex generators is reduced, furthermore it is both time consuming and expensive to re-fit them again.